The live per-path fs.watch handles, keyed by watched path — the same object the watcher
mutates, not a copy. A PARTIAL view: the parent-directory watchers, rescan intervals and
symlink pollers killFileWatchers also owns are not in here, so it answers "what is being
watched", not "every handle the watcher holds".
Usage
import { type WatchSession } from "lib/commands/test.ts";